Wait what is the international exam? Is that like IB or a different form for international students
@GreenPinkAmber Thank you! Why is the bond from the central atom to H weak if the molecule has more Os bonded to it? I also heard the conjugate base is more stable because of an additional electronegative oxygen atom (correct choice from practice exam)…is this true?
The molecule would become more polar and more negative towards the side with the oxygens. A polar bond is stronger than a non-polar bond. I would also assume that the (central)-H is weaker than the (central)-O because the O is more likely to be double bonded like in a carboxyl group (propanoic acid is an example).
Not all conjugate bases have oxygen in them so your second question depends on the AP question itself.
My teacher had the 2015 AP (i believe it was international) MC test. I got a 4 on it but the FRQs were crazy hard compared to the 2016 test. The 2015 AP MC was easier than 2016 AP MC… but that is just my opinion.
@bsdsj22 Thanks for the clear explanation :). The test you took is the international version though, right? So I think my test will be different, but I don’t know.
The AP HuG test last year was the same test administered stateside. But the APWH last year had two different tests. Last year’s AP chem students confirmed that they had the 2015 frqs posted on the CB website. It really differs I think. I’m certain it’s the same AP chem test tho. GL tomorrow
@JuicyMango If you have the Barron’s book they do a better job explaining the strength relative to the number of things bonded and the other various things that determine strength. The short answer is that the pull from the Os onto the central atom is greater therefore the net pull on the H is reduced. But in polyprotic acids it gets kind of confusing based off the number of Hs. I believe the only strong polyprotic acid is H2SO4, but it is strong only for the first H; meaning that the first H is more weakly bonded than the second, causing it to break off easier.
ACID STRENGTH: Two major factors:
- Stability of conjugate base: This is the easiest way to explain why acid strength decreases as H atoms are lost (e.g., why H2SO4 is stronger than HSO4-).
- Strength of O-H bond. O, N, and F are very electronegative, so they draw electron density away from the O-H bond. This causes the O-H to become weaker, and it is broken more readily (smaller bond dissocation energy). It is for this reason that an increase in the number of unbonded oxygens (i.e., an oxygen without an O-H bond) causes acids to become stronger.
Wrote the international AP exam. MCQs were extremely logical and way tougher compared to past year’s papers. Free response questions were good on the other hand but MCQs really got to most of us 
Hoping for a 4.
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Multiple choice was quite difficult. Free response on the other hand was a piece of cake!
I thought it was the opposite. MC was easy and FRQ had 2-4 that I didn’t know.
Multiple choice was very hard but free response was extremely simple.
I thought MC was ok and FRQs…eh some were a bit iffy…anyone taking the Chem SAT? If so, this week or June?
Junio
Yeah, I’m taking the Chem SAT later this week. :\ Is there anything specific we should know for that test that’s different from what we’ve studied for AP Chem?
I’ve taken a look at some organic and nuclear chemistry, but other than that, I’ve really only studied for AP Chem.
@infinityj I’m taking it in June, but you need to know the following that weren’t directly tested on the AP Exam:
-Phase diagrams
-Quantum numbers for electrons
-Lewis acids & bases
-Molality & colligative properties
-A full set of solubility rules
-Organic nomenclature basics (including functional groups) & Isomerism
-Radioactivity basics
(Source: https://www.adriandingleschemistrypages.com/sat/sat-subject-test-chemistry-2016/ ← his blog is super helpful)
Well, at least 1 exam down…4 to go…
I had to leave one of the FRQ blank but thought the MCQ were pretty easy… Anyone else not finish so I can feel better??
I felt the same I ran out of time and had to leave an FRQ blank
Ahhh its okay buddy. I had a lot of time left after the fr portion of the test. Maybe #6 was tricky…
i thought #6 was tricky too! i’m just glad the ap chem test is over.